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Title: SALMONELLA IN DAIRY OPERATIONS IN THE UNITED STATES: PREVALENCE AND ANTIMICROBIAL DRUG SUSCEPTIBILITY

Author
item BLAU, D - USDA-APHIS
item MCCLUSKEY, B - USDA-APHIS
item Ladely, Scott
item DARGATZ, D - USDA-APHIS
item Cray, Paula
item FERRIS, K - USDA-APHIS
item HEADRICK, M - FDA/CVM

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/31/2004
Publication Date: 10/20/2005
Citation: Blau, D.M., Mccluskey, B.J., Ladely, S.R., Dargatz, D.A., Cray, P.J., Ferris, K.E., Headrick, M.L. 2005. Salmonella in dairy operations in the united states: prevalence and antimicrobial drug susceptibility. Journal of Food Protection.696-702.

Interpretive Summary: Salmonella serotypes are important foodborne pathogens of humans that can be acquired through consumption of contaminated meat and dairy products. Salmonella infection also can be a significant animal health issue. As part of a national study of U.S. dairy operations conducted between March and September 2002, fecal samples were collected from representative cows in 97 dairy herds in 21 states and were cultured to determine the prevalence of Salmonella shedding. Salmonella was recovered from the feces of at least one cow in 30.9% of the herds. Overall, 7.3% of fecal samples were culture positive for Salmonella. The three most frequent recovered serotypes were Salmonella Meleagradis (24.1%, Salmonella Montevideo (11.9%), and Salmonella typhimurium (9.9%). The susceptibilities of Salmonella isolates recovered were determined using a panel of 16 antimicrobial drugs. Salmonella isolates recovered from dairy cows had relatively little resistance to these antimicrobial agents; 83.0% of the isolates were susceptible to all antimicrobials tested. This study provides updated information on the prevalence and susceptibility patterns of Salmonella in dairy herds and on cow and herd characteristics and contributes to our understanding of the ecology of Salmonella in the dairy farm environment. It is particularly useful for epidemiologist and animal and public health specialists as they design ways to reduce Salmonella in food animals.

Technical Abstract: Salmonella serotypes are important foodborne pathogens of humans that can be acquired through consumption of contaminated meat and dairy products. Salmonella infection also can be a significant animal health issue. As part of a national study of U.S. dairy operations conducted between March and September 2002, fecal samples were collected from representative cows in 97 dairy herds in 21 states and were cultured to determine the prevalence of Salmonella shedding. Salmonella was recovered from the feces of at least one cow in 30.9% of the herds. Overall, 7.3% of fecal samples were culture positive for Salmonella. The three most frequent recovered serotypes were Salmonella Meleagradis (24.1%, Salmonella Montevideo (11.9%), and Salmonella typhimurium (9.9%). The susceptibilities of Salmonella isolates recovered were determined using a panel of 16 antimicrobial drugs. Salmonella isolates recovered from dairy cows had relatively little resistance to these antimicrobial agents; 83.0% of the isolates were susceptible to all antimicrobials tested. This study provides updated information on the prevalence and susceptibility patterns of Salmonella in dairy herds and on cow and herd characteristics. These data contribute to our understanding of the ecology of Salmonella in the dairy farm environment.